Spitfire Glow Classic 54mm F4 99A wheels p19235 One of the most popular reel brands ever! Of course the Bighead logo also contributes to awareness. What sets Spitfire apart however is the polyurethane formulas they use for their reels. These reels are the Classic Series made with the unique and incomparable Spitfire Formula Four urethane formula also known as F4. The wheels have low abrasion roll cleanly and slide in a controlled manner. Flat spots are almost unthinkable. The Spitfire F4 reels are simply the best reels on the market!